Sir Alex Ferguson says Shinji Kagawa will become a huge asset for Manchester United when he adjusts to the physicality of the Premier League

Manchester United manager Sir Alex Ferguson believes midfielder Shinji Kagawa's improvement will continue despite the Japanese international having struggled to find his feet since his summer move to Old Trafford.

Kagawa joined United from Borussia Dortmund having flourished in helping to deliver successive Bundesliga titles, but has found adapting to English football a tough ask with a mid-season knee-injury disrupting his season.

But Ferguson is willing to give Kagawa time, claiming the contrast in pace of the top flight compared with Germany is exposing the 23 year old's lack of physical presence.

"He's come from an environment that is completely different," he told the United website. "I think the difference between German football and English football has been shown. In Germany you can't foul. It's foul after foul.

"The Premier League is completely different as there's physical contact in our game and it's different to Germany but, next year, he'll be better."

After a disappointing performance against Real Madrid in the Champions League, Ferguson has leapt to the midfielder's defence after his first half impact.

"In the first half an hour [in midweek] he was terrific as he kept making these great runs through them, which we thought was going to be one of our biggest assets in the game," Ferguson explained.

"He was just unlucky that he had a couple of heavy touches on the ball when he made runs past Robin van Persie. He kept opening them up but people don't see that, which is a wee bit unfair, as he did really well for us in the first half."